This invention relates to a gas-insulated substation of the type in which transformers are arranged on a first flat floor (plane) and a gas-insulated switching apparatus is arranged on a second flat floor (plane) above the first floor.
A substation of this type is disclosed, for example, in the Japanese Patent Laid-open Specification No. 32455/1975, in which transformers on the first floor are connected with the gas-insulated switching apparatus positioned at the upper portion thereof through branch bus-bars and the branch bus-bars are drawn out from one sides of transformers in the same direction, but there is no specific disclosure relating to the bus-bar arrangement interconnecting the respective transformers.
In a case where it is required to receive power from two circuits by using two transformers which are arranged on a floor in a substation different from that on which the gas-insulated switching apparatus is disposed, it is important to shorten the lengths of the branch bus-bars which interconnect the transformers and the gas-insulated switching apparatus and the length of a main bus-bar connecting the transformers with each other from a view point of compactness of the substation. Particularly, this fact is important for the substation installed in the interior of a building having a limited inner space. Generally, in a usual substation, primary sides of the respective transformers for receiving power are connected respectively to corresponding cable heads connected to power sources through the branch bus-bars with which disconnecting switches are connected and the intermediate portions of the disconnecting switches of the respective branch bus-bars are connected by the main bus-bar.
In an actual three-phase arrangement of the substation of the type described above, the branch bus-bars extend from the same one sides of two transformers in the same direction and the main bus-bars interconnect the both transformers through the branch bus-bars. Each of these main bus-bars in such arrangement has a considerably long length and heavy weight and this fact presents severe problems for the substation particularly installed in the interior of a building.